Bechthold (1939), Pocock (1941a), and Lekagul and McNeeley (1977) included auropunctatus. Wells (1989) discussed the situation for the morphotypes in Indochina. Nellis (1989) considered auropunctatus as a separate species. Taylor and Matheson's (1999) skull morphometic study showed that the oriental subspecies can be distinguished from the northern and western subspecies based on a phenetic analysis of skull measurements. Ghose (1965) separated palustris from javanicus. Wenzel and Haltenorth (1972) and Corbet and Hill (1992) considered palustris, auropunctatus, and javanicus as conspecific, which is followed here.